/*
** $Id: loslib.c,v 1.65.1.1 2017/04/19 17:29:57 roberto Exp $
** Standard Operating System library
** See Copyright Notice in lua.h
*/

#define loslib_c
#define LUA_LIB

#include "lprefix.h"

#include <errno.h>
#include <locale.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

/*
** {==================================================================
** List of valid conversion specifiers for the 'strftime' function;
** options are grouped by length; group of length 2 start with '||'.
** ===================================================================
*/
#if !defined(LUA_STRFTIMEOPTIONS) /* { */

/* options for ANSI C 89 (only 1-char options) */
#define L_STRFTIMEC89 "aAbBcdHIjmMpSUwWxXyYZ%"

/* options for ISO C 99 and POSIX */
#define L_STRFTIMEC99                       \
    "aAbBcCdDeFgGhHIjmMnprRStTuUVwWxXyYzZ%" \
    "||"                                    \
    "EcECExEXEyEY"                          \
    "OdOeOHOIOmOMOSOuOUOVOwOWOy" /* two-char options */

/* options for Windows */
#define L_STRFTIMEWIN         \
    "aAbBcdHIjmMpSUwWxXyYzZ%" \
    "||"                      \
    "#c#x#d#H#I#j#m#M#S#U#w#W#y#Y" /* two-char options */

#if defined(LUA_USE_WINDOWS)
#define LUA_STRFTIMEOPTIONS L_STRFTIMEWIN
#elif defined(LUA_USE_C89)
#define LUA_STRFTIMEOPTIONS L_STRFTIMEC89
#else /* C99 specification */
#define LUA_STRFTIMEOPTIONS L_STRFTIMEC99
#endif

#endif /* } */
/* }================================================================== */

/*
** {==================================================================
** Configuration for time-related stuff
** ===================================================================
*/

#if !defined(l_time_t) /* { */
/*
** type to represent time_t in Lua
*/
#define l_timet lua_Integer
#define l_pushtime(L, t) lua_pushinteger(L, (lua_Integer)(t))

static time_t l_checktime(lua_State* L, int arg)
{
    lua_Integer t = luaL_checkinteger(L, arg);
    luaL_argcheck(L, (time_t)t == t, arg, "time out-of-bounds");
    return (time_t)t;
}

#endif /* } */

#if !defined(l_gmtime) /* { */
/*
** By default, Lua uses gmtime/localtime, except when POSIX is available,
** where it uses gmtime_r/localtime_r
*/

#if defined(LUA_USE_POSIX) /* { */

#define l_gmtime(t, r) gmtime_r(t, r)
#define l_localtime(t, r) localtime_r(t, r)

#else /* }{ */

/* ISO C definitions */
#define l_gmtime(t, r) ((void)(r)->tm_sec, gmtime(t))
#define l_localtime(t, r) ((void)(r)->tm_sec, localtime(t))

#endif /* } */

#endif /* } */

/* }================================================================== */

/*
** {==================================================================
** Configuration for 'tmpnam':
** By default, Lua uses tmpnam except when POSIX is available, where
** it uses mkstemp.
** ===================================================================
*/
#if !defined(lua_tmpnam) /* { */

#if defined(LUA_USE_POSIX) /* { */

#include <unistd.h>

#define LUA_TMPNAMBUFSIZE 32

#if !defined(LUA_TMPNAMTEMPLATE)
#define LUA_TMPNAMTEMPLATE "/tmp/lua_XXXXXX"
#endif

#define lua_tmpnam(b, e)               \
    {                                  \
        strcpy(b, LUA_TMPNAMTEMPLATE); \
        e = mkstemp(b);                \
        if (e != -1)                   \
            close(e);                  \
        e = (e == -1);                 \
    }

#else /* }{ */

/* ISO C definitions */
#define LUA_TMPNAMBUFSIZE L_tmpnam
#define lua_tmpnam(b, e)         \
    {                            \
        e = (tmpnam(b) == NULL); \
    }

#endif /* } */

#endif /* } */
/* }================================================================== */

static int os_execute(lua_State* L)
{
    const char* cmd = luaL_optstring(L, 1, NULL);
    int stat = system(cmd);
    if (cmd != NULL)
        return luaL_execresult(L, stat);
    else
    {
        lua_pushboolean(L, stat); /* true if there is a shell */
        return 1;
    }
}

static int os_remove(lua_State* L)
{
    const char* filename = luaL_checkstring(L, 1);
    return luaL_fileresult(L, remove(filename) == 0, filename);
}

static int os_rename(lua_State* L)
{
    const char* fromname = luaL_checkstring(L, 1);
    const char* toname = luaL_checkstring(L, 2);
    return luaL_fileresult(L, rename(fromname, toname) == 0, NULL);
}

static int os_tmpname(lua_State* L)
{
    char buff[LUA_TMPNAMBUFSIZE];
    int err;
    lua_tmpnam(buff, err);
    if (err)
        return luaL_error(L, "unable to generate a unique filename");
    lua_pushstring(L, buff);
    return 1;
}

static int os_getenv(lua_State* L)
{
    lua_pushstring(L, getenv(luaL_checkstring(L, 1))); /* if NULL push nil */
    return 1;
}

static int os_clock(lua_State* L)
{
    lua_pushnumber(L, ((lua_Number)clock()) / (lua_Number)CLOCKS_PER_SEC);
    return 1;
}

/*
** {======================================================
** Time/Date operations
** { year=%Y, month=%m, day=%d, hour=%H, min=%M, sec=%S,
**   wday=%w+1, yday=%j, isdst=? }
** =======================================================
*/

static void setfield(lua_State* L, const char* key, int value)
{
    lua_pushinteger(L, value);
    lua_setfield(L, -2, key);
}

static void setboolfield(lua_State* L, const char* key, int value)
{
    if (value < 0) /* undefined? */
        return;    /* does not set field */
    lua_pushboolean(L, value);
    lua_setfield(L, -2, key);
}

/*
** Set all fields from structure 'tm' in the table on top of the stack
*/
static void setallfields(lua_State* L, struct tm* stm)
{
    setfield(L, "sec", stm->tm_sec);
    setfield(L, "min", stm->tm_min);
    setfield(L, "hour", stm->tm_hour);
    setfield(L, "day", stm->tm_mday);
    setfield(L, "month", stm->tm_mon + 1);
    setfield(L, "year", stm->tm_year + 1900);
    setfield(L, "wday", stm->tm_wday + 1);
    setfield(L, "yday", stm->tm_yday + 1);
    setboolfield(L, "isdst", stm->tm_isdst);
}

static int getboolfield(lua_State* L, const char* key)
{
    int res;
    res = (lua_getfield(L, -1, key) == LUA_TNIL) ? -1 : lua_toboolean(L, -1);
    lua_pop(L, 1);
    return res;
}

/* maximum value for date fields (to avoid arithmetic overflows with 'int') */
#if !defined(L_MAXDATEFIELD)
#define L_MAXDATEFIELD (INT_MAX / 2)
#endif

static int getfield(lua_State* L, const char* key, int d, int delta)
{
    int isnum;
    int t = lua_getfield(L, -1, key); /* get field and its type */
    lua_Integer res = lua_tointegerx(L, -1, &isnum);
    if (!isnum)
    {                      /* field is not an integer? */
        if (t != LUA_TNIL) /* some other value? */
            return luaL_error(L, "field '%s' is not an integer", key);
        else if (d < 0) /* absent field; no default? */
            return luaL_error(L, "field '%s' missing in date table", key);
        res = d;
    }
    else
    {
        if (!(-L_MAXDATEFIELD <= res && res <= L_MAXDATEFIELD))
            return luaL_error(L, "field '%s' is out-of-bound", key);
        res -= delta;
    }
    lua_pop(L, 1);
    return (int)res;
}

static const char* checkoption(lua_State* L, const char* conv, ptrdiff_t convlen, char* buff)
{
    const char* option = LUA_STRFTIMEOPTIONS;
    int oplen = 1; /* length of options being checked */
    for (; *option != '\0' && oplen <= convlen; option += oplen)
    {
        if (*option == '|') /* next block? */
            oplen++;        /* will check options with next length (+1) */
        else if (memcmp(conv, option, oplen) == 0)
        {                              /* match? */
            memcpy(buff, conv, oplen); /* copy valid option to buffer */
            buff[oplen] = '\0';
            return conv + oplen; /* return next item */
        }
    }
    luaL_argerror(L, 1, lua_pushfstring(L, "invalid conversion specifier '%%%s'", conv));
    return conv; /* to avoid warnings */
}

/* maximum size for an individual 'strftime' item */
#define SIZETIMEFMT 250

static int os_date(lua_State* L)
{
    size_t slen;
    const char* s = luaL_optlstring(L, 1, "%c", &slen);
    time_t t = luaL_opt(L, l_checktime, 2, time(NULL));
    const char* se = s + slen; /* 's' end */
    struct tm tmr, *stm;
    if (*s == '!')
    { /* UTC? */
        stm = l_gmtime(&t, &tmr);
        s++; /* skip '!' */
    }
    else
        stm = l_localtime(&t, &tmr);
    if (stm == NULL) /* invalid date? */
        return luaL_error(L, "time result cannot be represented in this installation");
    if (strcmp(s, "*t") == 0)
    {
        lua_createtable(L, 0, 9); /* 9 = number of fields */
        setallfields(L, stm);
    }
    else
    {
        char cc[4]; /* buffer for individual conversion specifiers */
        luaL_Buffer b;
        cc[0] = '%';
        luaL_buffinit(L, &b);
        while (s < se)
        {
            if (*s != '%') /* not a conversion specifier? */
                luaL_addchar(&b, *s++);
            else
            {
                size_t reslen;
                char* buff = luaL_prepbuffsize(&b, SIZETIMEFMT);
                s++;                                   /* skip '%' */
                s = checkoption(L, s, se - s, cc + 1); /* copy specifier to 'cc' */
                reslen = strftime(buff, SIZETIMEFMT, cc, stm);
                luaL_addsize(&b, reslen);
            }
        }
        luaL_pushresult(&b);
    }
    return 1;
}

static int os_time(lua_State* L)
{
    time_t t;
    if (lua_isnoneornil(L, 1)) /* called without args? */
        t = time(NULL);        /* get current time */
    else
    {
        struct tm ts;
        luaL_checktype(L, 1, LUA_TTABLE);
        lua_settop(L, 1); /* make sure table is at the top */
        ts.tm_sec = getfield(L, "sec", 0, 0);
        ts.tm_min = getfield(L, "min", 0, 0);
        ts.tm_hour = getfield(L, "hour", 12, 0);
        ts.tm_mday = getfield(L, "day", -1, 0);
        ts.tm_mon = getfield(L, "month", -1, 1);
        ts.tm_year = getfield(L, "year", -1, 1900);
        ts.tm_isdst = getboolfield(L, "isdst");
        t = mktime(&ts);
        setallfields(L, &ts); /* update fields with normalized values */
    }
    if (t != (time_t)(l_timet)t || t == (time_t)(-1))
        return luaL_error(L, "time result cannot be represented in this installation");
    l_pushtime(L, t);
    return 1;
}

static int os_difftime(lua_State* L)
{
    time_t t1 = l_checktime(L, 1);
    time_t t2 = l_checktime(L, 2);
    lua_pushnumber(L, (lua_Number)difftime(t1, t2));
    return 1;
}

/* }====================================================== */

static int os_setlocale(lua_State* L)
{
    static const int cat[] = {LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME};
    static const char* const catnames[] = {"all", "collate", "ctype", "monetary", "numeric", "time", NULL};
    const char* l = luaL_optstring(L, 1, NULL);
    int op = luaL_checkoption(L, 2, "all", catnames);
    lua_pushstring(L, setlocale(cat[op], l));
    return 1;
}

static int os_exit(lua_State* L)
{
    int status;
    if (lua_isboolean(L, 1))
        status = (lua_toboolean(L, 1) ? EXIT_SUCCESS : EXIT_FAILURE);
    else
        status = (int)luaL_optinteger(L, 1, EXIT_SUCCESS);
    if (lua_toboolean(L, 2))
        lua_close(L);
    if (L)
        exit(status); /* 'if' to avoid warnings for unreachable 'return' */
    return 0;
}

static const luaL_Reg syslib[] = {{"clock", os_clock},
                                  {"date", os_date},
                                  {"difftime", os_difftime},
                                  {"execute", os_execute},
                                  {"exit", os_exit},
                                  {"getenv", os_getenv},
                                  {"remove", os_remove},
                                  {"rename", os_rename},
                                  {"setlocale", os_setlocale},
                                  {"time", os_time},
                                  {"tmpname", os_tmpname},
                                  {NULL, NULL}};

/* }====================================================== */

LUAMOD_API int luaopen_os(lua_State* L)
{
    luaL_newlib(L, syslib);
    return 1;
}
